There are conventional high electron mobility transistors (HEMTs) having a semiconductor multilayer structure including a carrier travel layer and a carrier supply layer.
In recent years, GaN-HEMTs having a HEMT structure including an electron travel layer containing GaN and an electron supply layer containing AlGaN, the electron travel layer and the electron supply layer being stacked, are under active development based on heterojunctions of AlGaN and GaN, which are GaN compound semiconductors.
GaN has a bandgap of about 3.4 eV, which is larger than the bandgap (about 1.1 eV) of Si and the bandgap (about 1.4 eV) of GaAs, and therefore is a material having high breakdown field strength. GaN is also a material having high saturated electron velocity. Therefore, GaN is promising as a material for achieving semiconductor devices, enabling high-voltage operation, for power supplies capable of obtaining high power. GaN-HEMTs are expected as, for example, high-efficiency switching elements for use in power supply units provided in electronic apparatuses or high-voltage power devices for use in electric vehicles.
A semiconductor chip including such a GaN-HEMT is mounted on a substrate such as a circuit board or a stage of a lead frame.
A technique for mounting the semiconductor chip on the substrate is as follows: the back surface of the semiconductor chip is bonded to a semiconductor chip-mounting region of the substrate using, for example, a die bonding agent such as solder or an adhesive, thereby mounting the semiconductor chip on the substrate.
For related art, the following documents have been disclosed: Japanese Laid-open Patent Publication No. 2006-156437, Japanese Laid-open Patent Publication No. 6-132442, Japanese Laid-open Patent Publication No. 58-207645, and the like.